Breech block for use in firing subcalibre training cartridges from recoilless weapons



1970 E. w. WALLBERG ET AL 3,489,058

BREECH BLOCK FOR USE IN FIRING SUBGALIBRE TRAINING CARTRIDGES FROMRECOILLESS WEAPONS Filed April 16, 1968 2 Sheets-Sheet 1 Q! T C:

kiarl Eng AM erssw;

Jan. 13, 1970 E. w. WALLBERG ET AL 3,489,058

BREECH BLOCK FOR USE IN FIRING SUBCALIBRE TRAINING CARTRIDGES FiledApril 16, 1968 FROM RECOILLES S WEAPONS 2 Sheets-Sheet 2 Fig-7 da wgqiwri mile-r850 )3 1 BY United States Patent 3,489,058 BREECH BLOCK FOR USEIN FIRING SUB- CALIBRE TRAINING CARTRIDGES FROM RECOILLESS WEAPONS" ErikWilhelm Wallberg, Vallingby, and Karl-Erik Andersson, Eskilstuna,Sweden, assignors to Forsvarets Fabriksverk, Eskilstuna, Sweden, acorporation of Sweden Filed Apr. 16, 1968, Ser. No. 721,654 Int. Cl.F41f 3/02, 15/00 US. Cl. 89--1.705 6 Claims ABSTRACT OF THE DISCLOSURE Abreech block for firing subcalibre cartridges from recoilless weapons,said breech block having a firing pin for the subcalibre cartridge whichis actuated by an explosive charge in an auxiliary cartridge, therebeing a rearward opening from a chambef containing said auxiliarycartridge through which a rearwardly directed flame is fired in order tosimulate the actual function of the weapon when it is fired with fullcalibre cartridges.

Description The present invention relates to a breech block for use intraining military personnel for firing recoilless weapons with sidetriggering.

An object of the present invention is to imitate the actual function ofa recoilless weapon when it is fired with a full calibre cartridge.

In training personnel for firing recoilless weapons, one generally usesa special round or frame to be inserted in the barrel of the recoillessweapon, said round or frame comprising a subcalibre barrel. In saidround or frame there is an easily removable breech block which isprovided with a fastening means for the subcalibre training ammunitionand with means for firing said ammunition. In known breech blocks ofthis kind, for example the breech block shown in the Swedish Patent199,475, said firing means comprises at least one firing pin, a hammer,and a safety catch.

The present invention relates to a breech block which is provided with acartridge chamber for an auxiliary cartridge which is adapted to actuatesaid firing pin to engagement with the subcalibre cartridge and by thismeans to provide a substitute for the hammer. According to the inventionthere is a rearwardly directed flame opening from said auxiliarycartridge chamber through which a rearwardly directed flame is beingprojected, in order to simulate the actual function of the recoillessarm when it is used together with ammunition of full calibre.

In the following, the invention will be described more in detail,references being bad to the accompanied drawings, in which:

FIG. 1 is a longitudinal section of a breech block according to theinvention, and

FIG. 2 is a transversal section of said breech block along the lineII-II in FIG. 1,

FIG. 3 is a section through a cartridge receiving frame or round to beused in a recoilless arm, with a breech block according to theinvention, said round comprising a barrel for a subcalibre cartridge,

FIG. 4 is a section along the line IV-IV in FIG. 3, as viewed in thedirection of the arrows,

FIG. 5 is a view from the rear of the device shown in FIG. 3 andillustrating the breech block in a safety and a non-safety position,

FIG. 6 is a rear view of the breech block illustrating two differentpositions of a tiltable side portion of said breech block, and

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FIG. 7 is a longitudinal section through the upper half of the breechblock illustrating a safety device in its non-safety position.

In the drawings, the breech block is designated I. Said breech block isprovided with a flange 2 at the front end thereof, said flange 2 formingone part of a bayonet fixing, as will be apparent from FIG. 4, andserving for keeping the breech block fastened in a special round orframe 32, as will be described in connection with FIGS. 3 and 4, saidround or frame 32 being in turn adapted to be inserted in the rear endof a recoilless weapon. In said flange 2 there is a fitting 3 forkeeping a subcalibre training cartridge and behind said fitting 3 thereis a longitudinal bore 4 for a firing pin 5. The firing pin 5 is kept ina rear, rest position by a helical spring 6, against a stopper 7. At itsrear end, the firing pin 5 is provided with a flange 8 located in anenlarged portion 4a of the bore 4, said enlarged portion 4a having alength exceeding the axial length of the flange 8. The movement of thefiring pin 5 is thus limited to the distance between the flange 8 andthe annular surface 9 between the bore 4 and the enlarged portion 4a.The breech block is provided with a laterally open chamber 10, saidchamber having the shape of a cylindrical transverse bore, the centralline of said chamber 10 being located in the same plane as the centralline of the bore 4, but disposed at a right angle to the latter. Thechamber 10' is intended to receive an auxiliary cartridge, not shown,the envelope of which being made of a flexible, plastic material andhaving a mantle wall which engages the rear end surface of the flange 8of the firing pin 5. Behind the cartridge chamber 10, the breech blockis provided with a bore 11 which communicates with the cartridge chamber10 and forms a rearwardly directed opening from the chamber 10. The bore11 is coaxial with the bore 4. The laterial opening of the chamber 10 iscovered by a side portion 1a comprising a number of parts which are kepttogether. The outermost member 12 of said side portion 1a has the shapeof a cap which partly covers the other parts and has an outer surface 13which is matched to the cylindrical, inner surface of the opening in theround 32, FIG. 3, in which the breech block is intended to be inserted.Said side portion 1a is pivoted about an axis 14. Therefore, when thebreech block is removed from said round 32, said side portion 1a can betilted open to uncover the lateral opening of the chamber 10, in orderto facilitate changing of the auxiliary cartridge received in thechamber 10. In the cap-shaped member 12, a second firing pin 16 islocated, the igniting tip of which is located just in the centre of theopening of the chamber 10. Said second firing pin 16 is adapted toignite the auxiliary cartridge received in said chamber 10. Thecap-shaped member 12 is arranged to be displaced inwardly together withthe firing pin 16 against the force of a helical spring 17, surroundingsaid firing pin 16. This displacement is a parallel displacement of themember 12, and for that purpose, the member 12 is guided by means of twoguiding pins 18 which are fastened in an inner part belonging to thetiltable side portion 1a and which are freely. penetrating slots 19, 20in the side parts of the cap-shaped member 12. The guiding pins 18 areshaped as slotted, tubular members which are forced into bores in saidinner part and kept in place by spring action of said tubular members.

By turning the breech block, the latter can be moved into one or theother of two positions, one of which is a safety position and the otheris a non-safety position. In the non-safety position shown in full linesin FIG. 5, the cap-shaped member 12 is located under a detonating cap 30which is adapted to be actuated by a lateral triggering device belongingto the recoilless weapon. The cap-shaped member 12 is arranged to bepressed inwardly by the gas pressure developed by said detonating cap30. However, when the breech block is turned to th safety position shownin dash-dotted lines in FIG. 5, the capshaped member 12 is locatedlaterall of said detonating cap 30. In this position, firing of therecoilless weapon will not result in any displacement of the member 12and, therefore, does not result in ignition of the auxiliary cartridgereceived in the chamber 10.

When the breech block is removed from the round 32, said breech blockhas to be put to safety condition against firing, which means thatinward pressure of the capshaped member 12 should be prevented. A safetycatch is provided by an inner member 21, belonging to the tiltable sideportion 1a. The member 21 is slidable in the longitudinal direction ofthe breech block. When the breech bloc-k is removed from said frame, themember is kept in the safety position illustrated in FIG. 1, by ahelical spring 22. In this position two projections 23, 24 are locatedopposite to two corresponding projections 25, 26 belonging to thecap-shaped member 12, and by this means the cap-shaped member 12 withthe firing pin 16 can not be displaced inwardly. When the breech blockis inserted into the frame or round 32, a projection 27 belonging to themember 21 will engage a part 31 (FIG. 7) belonging to the round 32.Therefore, the member 21 will be pushed backwards against the action ofthe spring 22 to a position where the projections 23, 24 are displacedto the right from the position shown in FIG. 1 to the position shown inFIG. 7. In this position, the safety device is inactive because theprojections 23, 24 are no longer located in alignment with theprojections 25, 26.

In operation, the chamber is open and freely accessible when the breechblock is removed from said frame 32 and when the side member 1a of thebreech block is tilted up to the position shown by dash-dotted lines inFIG. 6. In this position, a cartridge may be inserted into the chamber10 and, thereafter, the side portion 1a may be clasped down to theposition shown in FIGS. 1 and 2. In this position, the member 12 is,however, prevented from being pressed inwardly and, therefore, thecartridge received in the bore 10 cannot be ignited in this position. Asubcalibre cartridge is then inserted into the fitting 3 and the breechblock is inserted into the round 32 and pressed inwardly and turned to afixed position, whereby the safety device is made inactive as describedin the foregoing. Before firing the weapon, the breech block is furtherturned to the position in which the cap-shaped member 12 is locatedunder the detonating cap in the round 32, as shown in full lines in FIG.5. By ignition of the detonating cap 30 by actuating the triggeringdevice of the recoilless weapon, a gas pressure is developed, which issufiicient to rapidly press the member 12 inwardly and thereby also topress the firing pin 16 against the ignition cap of the auxiliarycartridge received in the chamber 10, so that the gunpowder in saidcartridge will be ignited. The gas pressure developed in the chamber 10expands the flexible mantle wall of the auxiliary cartridge envelopeinto the opening of the bores 4 and 11. The firing pin 5, the rear endsurface of which is in contact with the auxiliary cartridge in thechamber 10, will now be pushed forwards, so that the left part of saidfiring pin will strike against the ignition cap of the subcalibrecartridge inserted into the fitting 3. Immediately thereafter the mantleWall of the auxiliary cartridge in the chamber 10 will be broken throughwhere the bore 11 opens into the chamber 10. When this occurs, however,the gunpowder gases are ex hausted rearwardly through the bore 11 andthe report obtained from that exhaustion is considerably more powerfulthan the report from the firing of the subcalibre cartridge attached tothe fitting 3. In addition to that, a flame will be projectedrearwardly.

After firing, the breech block can be removed from the round 32 and,thereafter, the empty subcalibre cartridge attached to the fitting 3 andthe rest of the plastic envelope of the cartridge in the bore 10 areremoved and new cartridges are inserted in the said locations. Thebreech block may again be inserted into the round 32 and, thereafter,the training weapon is again ready for use.

The training weapon may also be used charged with only the auxiliarycartridge received in the chamber 10' for blank firing exercise.

What we claim is:

1. In a breech block for a sub-calibre training cartridge for insertionlongitudinally into the barrel of a recoilless weapon comprising, a mainbody member having a generally prismatical shape in its longitudinaldirection, said main body member having a radial bore extending from oneside of the member and past its longitudinal center, said bore forming achamber for a fireindicating cartridge containing a fire-indicatingcharge and having an envelope having a mantle wall composed of flexiblematerial, said member having a further first central longitudinal boreextending from the radial bore to the rear end of said member, saidmember having a second central longitudinal bore extending from saidradial bore to the front end of the member, a fitting for receiving asub-calibre training cartridge where said second longitudinal boreterminates at the front end surface of said member, a firing pinslidably located in said second longitudinalbore, said firing pin havinga tip at its front end, said tip being directed toward the ignition capof a sub-calibre cartridge that is inserted in said fitting, a springfor urging said firing pin rearwardly away from the sub-calibrecartridge fitting, a piston portion at the rear end of the firing pin,the rear end of the piston portion being flush with the inner wallsurface of said radial bore when the firing pin is kept in its rearmostposition, a side portion mounted outside said main body member andcovering the opening of said radial bore, an auxiliary firing pin insaid side portion, said second firing pin having a tip directed towardthe ignition cap of the indicating cartridge in said radial bore, aspring for urging said auxiliary firing pin away from said indicatingcartridge, a cap-shaped member belongng to said side portion and beingdisplaceable radially inwardly, said cap-shaped member engaging saidauxiliary firing pin, said capshaped member forming a part of theoutermost mantle surface of the breech block, said cap-shaped memberbeing pressed inwardly by a side firing device of the recoilless weaponand upon such pressure actuating said auxiliary firing pin to ignite theauxiliary cartridge, whereupon the flexible mantle wall of the saidcartridge will bulge forwardly into the second longitudinal bore andpress the first firing pin toward the ignition cap of the subcalibrecartridge, the explosion of the fire-indicating charge further causingthe flexible mantle wall of the fireindicating cartridge to breakthrough into said first longitudinal bore and allow burning combustiongases to be thrown out backwardly from said breech bloc-k, thus audiblyand visually indicating the firing.

2. In a breech block according to claim 1, hinges connecting said sideportion to said main body member for allowing said side portion to betilted open to free the opening of said radial bore for enabling theexchange of said auxiliary cartridge to be made.

3. In a breech block according to claim 1, a cylindrical frame in whichthe assembly, comprising the said main body member and said side portionare inserted, said frame being insertable in the barrel of saidrecoilless weapon, an outer ignition cap in the mantle surface of saidframe for actuation by the side firing device of said recoilless weapon,a radial channel from said ignition cap to said side portion of saidassembly when said assembly is inserted in said frame, said channelallowing the combustion gases from said outer ignition cap to press saidside portion inwardly.

4. A breech block according to claim 3, in which said assembly of themain body member and the side portion are rotatable in said frame froman active position wherein said side portion registers with the openingof said radial chamber, to a safety position wherein said side portionis displaced from the opening of said channel.

5. In a breech block according to claim 4, wherein a bayonet fitting isemployed for locking said assembly in said frame, said locking takingplace in said active and safety positions, but said assembly beingunlocked and removable from said frame when in a position beyond eitherof said active or safety positions.

6. In a breech block according to claim 5, including a slidable memberbetween said cap-shaped member and said main body member, said slidablemember being kept from being pressed inwardly, a projection on saidslidable member which engages a projection on said frame when saidassembly is inserted in the frame and causes the slidable member to bedisplaced against the action of said spring to a position where the saidprojections on the slidable member are outside of the path of movementof the corresponding projections on said cap-shaped member.

References Cited UNITED STATES PATENTS 3,296,928 1/1967 Lubbers 42-77FOREIGN PATENTS 757,195 9/1956 Great Britain. 936,502 9/1963 GreatBritain. 1,122,876 1/1962 Germany.

SAMUEL W. ENGLE, Primary Examiner US. Cl. X.R. 8929, 10241

